JP6122020B2 - Rotor for electric machine and assembly method thereof - Google Patents

Description

  The present invention relates to a rotor for an electric machine, in particular a rotor having permanent magnets, and a system for fixing a magnet in an associated seat. The invention further relates to a method for assembling the rotor.

  The rotor of a motor with a known type of permanent magnet, especially used in brushless motors, is usually made of a laminated core, ie a thin metal laminate pack and coincides with the motor's axis of rotation. A core having a main axis.

  The rotor generally has a plurality of longitudinal slots and a central hole to accommodate the magnet and the drive shaft, which extend parallel to the main axis.

  This slot forms a kind of segment structure in the laminated core that forms the magnetic poles of the rotor, and each segment that remains connected to the central part of the laminated core that surrounds the hole in the drive shaft is adjacent to each other Separate the two slots.

  The magnets extend along the axis of the rotor, and the magnets are generally for a portion of each contact element at the outer end of the associated slot that is open on the outer surface of the rotor (excluding the contact element). In general, they are arranged in the radial direction.

  A common problem with this type of rotor is related to the manner in which the magnet is secured in the associated slot.

  The magnet must be mounted in the correct location in the slot for proper electromagnetic operation of the motor and so as not to cause vibration during motor operation.

  In a reference motor in accordance with the present invention, i.e. a motor with radially arranged magnets, one prior art solution bonds the magnets in the associated seat. A magnet with adhesive applied on the surface is inserted into its associated slot and held by a special instrument in contact with the outer contact element until the adhesive is cured .

  In a different embodiment, the magnet is held in place in the slot by the instrument and at the same time the rotor is inserted into a mold into which plastic is injected. In this way, the magnet is simultaneously pressed with the laminate and held in place by the plastic.

  The prior art solution described above is relatively expensive due to its assembly complexity.

  In another most commonly used embodiment, each magnet is abutted against the contact element by a radial pressure spring inserted between the magnet and the central portion of the laminated core. Kept in a state.

  These springs can be single (one for each magnet) or integrated in the form of a single annular element.

  In this solution, the main drawback is that in the case of a magnet, the corresponding spring may push the magnet in a direction that is not completely radial, due to mechanical dimensional tolerances for inserting the magnet, As a result of this, the magnet will only contact one of the provided contact elements, i.e. only one of the segments defining the slot.

  In some cases, there may be segments that are not stabilized by the magnet and thus vibrate during motor operation.

  Furthermore, the magnet may scrape off the contact element due to a reduction in the contact surface of the contact element.

  The main technical object of the invention is therefore to provide an electric machine motor which does not have the above-mentioned drawbacks.

  Another intent of the present invention is to provide a rotor that is relatively economical and easy to assemble.

  Yet another intent of the present invention is to provide a rotor that is free from the risk of mechanical vibration in use.

  The above objects and intentions are substantially achieved by an electric machine motor having the features defined in claim 1.

  Further features and advantages of the present invention will become more apparent in the detailed description which follows, with respect to preferred non-limiting embodiments of motors for electric machines shown in the accompanying drawings.

FIG. 1 is a partially exploded schematic perspective view of a first embodiment of an 8-pole rotor according to the present invention. 2 is a schematic perspective view of an enlarged detail of the rotor of FIG. 3 is a cross-section III-III of the detail of FIG. FIG. 4 is a schematic perspective view of the rotor shown in the drawing. FIG. 5 is a schematic perspective view of a detailed part of a second embodiment of a rotor according to the invention. FIG. 6 is a partially exploded schematic perspective view of a third embodiment of an 8-pole rotor according to the present invention. FIG. 7 is a schematic perspective view of a detailed portion of the rotor of FIG. FIG. 8 is a partially exploded schematic perspective view of a third embodiment of an 8-pole rotor according to the present invention. FIG. 9 is a schematic perspective view of a detailed portion of the rotor of FIG.

  With reference to the accompanying drawings, in particular FIGS. 1, 6 and 8, the number 1 indicates a rotor for an electric machine according to the invention.

  The rotor 1 includes a laminated core or pack 2 having a laminated structure having a main axis R, and a plurality of magnetic poles 3 a and 3 b that define a plurality of seats 4.

  The magnetic poles or teeth 3a, 3b are in the form of segments extending radially from the central nucleus of the laminated core 2.

  The seats 4 also extend radially (in length) along the main axis R and are each defined by a first magnetic pole 3a and by a second magnetic pole 3b.

  The rotor 1 comprises eight magnets 5 in the embodiment shown, each of which is inserted into a corresponding seat 4.

  The rotor 1 acts between each magnet 5 and the first magnetic pole 3a defining the associated seat 4 to push each magnet 5 toward the second magnetic pole 3b defining the seat 4. An elastic means for fixing the magnet 5 in the seat 4 is provided.

  As shown, each first magnetic pole 3a has two faces 6 that advantageously define a flat surface defining an adjacent seat 4, and each second magnetic pole 3b It has two faces 7 that define an adjacent seat 4 and are advantageously flat.

  In other words, each seat 4 is defined by a flat surface 6 of the first magnetic pole 3a and a flat surface 7 of the second magnetic pole.

  In the case of the seat 4, the surfaces 6, 7 defining the seat are located opposite to each other and parallel to each other, so that the elastic means causes the corresponding magnet 5 from the first magnetic pole 3 a to Press against the flat surface 7 of the two magnetic poles.

  The magnet 5 is in the shape of a parallelepiped and has a pair of parallel flat surfaces 8, 9. The magnet 5 preferably further has a smoothly polished outer surface.

  The number 8 in the accompanying drawings indicates the surface of the magnet 5 facing the magnetic pole 3a, and the number 9 indicates the surface of the magnet 5 facing the magnetic pole 3b, in particular the associated surfaces 6 and 7.

  The resilient means is shaped to press the flat surface 9 of the magnet 5 against the flat surface 7 of the corresponding second pole 3b that defines the associated seat 4.

  In the preferred embodiment shown, the elastic means comprises a plurality of springs 10.

  In general, the spring 10 is fork-shaped and is inserted on every other dent, ie, on the pole 3a in the accompanying drawings, which are shown by way of example only.

  Each spring 10 pushes two magnets 5 adjacent to each other, and these magnets 5 are toothed projections 3b located on the opposite side of the magnet 10 from the spring 10, as will be described in more detail below. Press against the surface 7.

  In this way, each dentition or magnetic pole 3a, 3b of the ferromagnetic material is held stationary by the magnet 5 surrounding it.

  Observing the positioning of the spring 10 in more detail, it should be noted that each pole 3a has an engagement means for the associated elastic means, ie an engagement means for the spring 10.

  More specifically, the engagement means for the spring 10 is in the form of a groove 11 on the face 6 of the magnetic pole 3a.

  The groove 11 extends parallel to the main axis R and in the case of the magnetic pole 3a is aligned according to a cylindrical surface having an axis that coincides with the main axis.

  The spring 10 is shaped to be pushed into the associated groove 11 after inserting the magnet 5 to completely fill the groove 11, and the spring 10 is made of a ferromagnetic material. Since it is preferable, the magnetic circuit is optimized.

  Thus, in general, this resilient means comprises a plurality of springs 10, each spring 10 being associated with a magnetic pole 3a in order to push the corresponding magnet 5 towards the magnetic pole 3b defining the associated seat 4. Yes.

  With particular reference to FIGS. 3, 4, 5, 7 and 9, the spring 10 for the rotor 1 according to the invention is shown in more detail.

  The spring 10 has a base stretch 12, from which two substantially parallel prongs 13, 14 are designed to engage the inside of the groove 11.

  The base length portion 12 is preferably curved so as to grip the magnetic pole 3a and cooperate to hold the protrusions 13, 14 in place.

  Furthermore, the base length portion 12 extends along a peripheral edge that is concentric with the rotor 1.

  The grooves 13, 14 are aligned along a cylindrical surface that extends parallel to the main axis R and has an axis that coincides with the main axis R.

  The protrusions 13 and 14 have a first linear length portion 15 and at least a second elastically bent wave-like length portion 16.

  The corrugated length portion 16 has convex portions located opposite to each other with respect to the magnetic pole 3 a, each facing the corresponding seat 4 and projecting inside the seat 4.

  The wave-like length portions 16 of the protrusions 13 and 14 act on the magnet 5 inserted into the two seats 4 adjacent to each other.

  This linear length portion 15 of the projections 13, 14 lays out a magnet 5 which is later pushed inside the seat 4 on its associated magnetic pole 3 a after the spring 10 has been placed in the rotor. Does not accept a portion of the spring 10 in the seat 4 for the first few millimeters.

  The magnet 5 and its associated seat 4 have a very small assembly tolerance of approximately one tenth of a millimeter, so that for proper positioning of the magnet 5 in the opening of the seat 4, a portion of the spring 10 is It is important that it does not exist.

  After inserting the magnet 5 into the seat 4, the spring 10 is fully extended in the associated groove 11 (except for a small part of the convex part 16 protruding to push the magnet) and the magnetic circuit Enables the completion of.

  Preferably, it is intended for a motor having an output of about 100-300 watts and a rotor with a laminated pack having a length of up to 20 mm and a diameter of up to 100 mm, FIG. 1 to FIG. In the first embodiment shown in FIG. 4, a spring 10 made of spring wire and having a single corrugated length 16 for each projection 13, 14 is sufficient.

  As shown in FIG. 5, it may be up to about 100 mm and therefore for a longer motor, preferably with a heavier magnet 5 in the case of the same diameter of the rotor 1. In the intended second embodiment, each of the protrusions 13, 14 of the spring 10 has a second wavy length portion 17 extending from the first wavy length portion 16.

  The second undulated length portions 17 each face towards the corresponding seat 4 for the magnet 5 and project inside the seat 4 in order to exert a pressing action on the corresponding magnet 5. And convex portions located on opposite sides of each other.

  A steel spring wire is preferably used for the above embodiment.

  The diameter of the wire is smaller than the depth of the associated groove 11 so that the protrusions 13, 14 of the spring 10, in particular the linear length 15, do not disturb the seat 4.

  In a third embodiment, it is preferable to be adapted for a rotor having a stack pack length of up to 20 mm and a diameter greater than or significantly greater than 100 mm, so that the magnet 5 has a larger radius than the solution described above. In the third embodiment shown in FIGS. 6 and 7 having a length in the direction, the spring 10 is shaped appropriately so as to exert an appropriate pressing action on the magnet 5. Made of metal strip.

  The shape of the spring 10 made of this metal strip matches the shape of the spring 10 made of wire, i.e. the spring 10 protrudes parallel to each other from the head or base part 12 and the base 12. Two protrusions 13, 14.

  The spring 10 extends substantially over the entire length of the rotor and has a length that is as large as the length of the corresponding tooth projection 3a.

  The width of the metal strip is selected based on the force to be applied to the magnet 5 and the weight of the magnet.

  In a manner similar to the embodiment described above, the protrusions 13, 14 have a first linear length portion 15 and at least a second elastically bent wave-like length portion 16.

  The corrugated length portion 16 has convex portions located on opposite sides, each facing the corresponding seat 4 and protruding inside the seat 4.

  The wave-like length portions 16 of the protrusions 13 and 14 act on the magnet 5 inserted into the two seats 4 adjacent to each other.

  This linear length portion 15 of the projections 13, 14 lays out a magnet 5 which is later pushed inside the seat 4 on its associated magnetic pole 3 a after the spring 10 has been placed in the rotor. Does not accept a portion of the spring 10 in the seat 4 for the first few millimeters.

  Alternatively, in an embodiment not shown, the metal strip springs are appropriately sized, made of wire, and spaced radially from one another along the pole 3a. It is replaced by two or more springs 10 of the type described above.

  As shown in FIG. 8, in a fourth embodiment, a longer motor up to about 100 mm and longer and having a diameter up to 100 mm and larger, and thus with heavier magnets. In this case, the protrusions 13, 14 of the spring 10 have a plurality of corrugated long portions 18, 19, 20 extending from the first corrugated length portion 16.

  The additional wavy length portions 18, 19, 20 are each opposed to the corresponding seat 4 for the magnet 5 and on the inside of the seat 4 in order to exert a pressing action on the corresponding magnet 5. Protruding convex portions located opposite to each other.

  Even a spring 10 made of a metal strip allows an initial linear length that allows proper positioning of the magnet 5 (in the opening of the corresponding seat 4) before inserting the magnet 5 into its corresponding seat. It should be understood that it has a portion 15.

  The wavy length portions 16, 17, 18, 19, 20 of the different springs 10 are suitably formed so as to exert a pressing force on the corresponding magnets 5 perpendicular to the surface of the magnets 5 that abut the springs 10. ing.

  This pressing force corresponds to a tangential force between the surface 9 on the opposite side of the magnet 5 and the surface 7 of the magnetic pole on which the spring 10 is pressed against and supported.

  Advantageously, the spring 10 is made of a ferromagnetic material, as described above, and, therefore, prior art so as not to short adjacent magnets and to lose electromagnetic flow. Less expensive than springs made of non-magnetic materials used in the solution.

  The use of a magnetic material for the spring 10 makes it possible to substantially eliminate the flow dispersion that would be present in the air of the spring 10 seat.

  In practice, the spring 10 pushes each magnet 5 tangentially to the circumference passing through the groove 11 in order to move each magnet 5 next to the corresponding magnetic pole 3b. The force pushing the magnet 5 is perpendicular to the magnet 5 so that a frictional force holding the magnet 5 in the seat 4 is generated on the entire surface 9 of the magnet located on the iron of the laminate pack 2. Act on.

  In order to evenly distribute the force of the spring 10 on the corresponding magnet, the spring 10 is positioned substantially on the intermediate area (with respect to the radial length) of the corresponding magnet 5.

  In the present invention, the spring 10 is bent and plastically deformed and is sufficient to press the magnet 5 against the surface 7 of the magnetic pole 3b after the magnet 5 has been placed and the heat of the magnet in use. Maintains elastic properties, suitable for accommodating expansion.

  Advantageously, a loss of a portion of the elastic properties allows proper sizing of the spring 10 with a preload value that is acceptable and suitable for pressing of the magnet 5.

  With particular reference to FIGS. 1, 2, 6 and 8, it should be noted that the laminated core 2 has a plurality of holes 21 in the magnetic poles 3 a, 3 b extending along the axis R.

  The purpose of these holes 21 is to reduce weight, and these holes 21 define engagement means in the rotor for instruments that move the rotor 1 during assembly of the motor.

  A preferred method for assembling the rotor 1 with the laminate pack 2 includes positioning all of the springs 10 across the associated pole 3a and inserting all of the magnets 5 simultaneously. .

  As an alternative, if one magnet 5 is inserted at a time, the magnetic poles 3a, 3b are provided with an instrument (not shown) comprising a plurality of pins that engage the holes 21 described above. In use, maintained in reciprocal alternating positions.

  With particular reference to FIG. 2, it should be noted that the laminated core 2 has a tooth-like protrusion 22 that acts on the magnet 5 at the outer peripheral edge of the magnetic pole 3. These tooth protrusions 22 extend longitudinally along the axis R and define a radial reference for positioning the magnet 5. Advantageously, the magnet 5 is held in the associated seat 4 as described above by friction between the surface 9 of the magnet 5 and the surface 7 of the magnetic pole 3b, rather than by the toothed projections 22 described above. ing.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Laminated core 3a, 3b Magnetic pole 4 Seat 5 Magnet 10 Spring 11 Groove 12 Base length part 13, 14 Groove 15 Linear length part 16 Wave-like length part

Claims (15)

A rotor for an electric machine,
A laminated core (2) having a main axis (R), and a plurality of magnetic poles (3a, 3b) defining a plurality of radial seats (4) extending along the main axis (R), and Each of the seats (4) is defined by a first magnetic pole (3a) and a second magnetic pole (3b) ;
The rotor is
E Bei a plurality of magnets being inserted into the seat (4) in (5), the seat and a spring (10) for securing the (4) the magnet (5) in,
The spring (10) in order to push each of the toward the second magnetic pole defining said seat and (4) (3b) magnet (5), and each of said magnets (5), said seat ( 4) In an electric machine rotor acting between said first magnetic pole (3b) defining 4)
The spring (10) is positioned so as to straddle the first magnetic pole (3a), and each spring (10) pushes the two magnets (5) adjacent to each other to the magnet (5). On the other hand, the rotor for an electric machine, wherein the magnet (5) is pressed against the surface of each second magnetic pole (3b) located on the opposite side of the spring (10) . The first magnetic pole (3a) has a first surface (6) defining the seat (4), and the second magnetic pole (3b) is a first surface defining the seat (4). Two surfaces (7), the first and second surfaces (6, 7) are parallel to each other, and the spring (10) moves the corresponding magnet (5) to the second surface The rotor for an electric machine according to claim 1, wherein the rotor is pressed against (7). The spring (10) comprises a plurality of springs (10), and at least one of said spring (10), the second pole toward said to (3b) magnets defining said seat (4) ( 5. The rotor for an electric machine according to claim 1, wherein the rotor corresponds to each first magnetic pole (3 a) for pressing each of 5). The spring (10) comprises a plurality of springs (10) having a base length portion (12) from which two mutually parallel protrusions (13, 14) extend, and the protrusions (13, 14) are first One linear length portion (15) and at least one elastically bent wavelike length portion (16), and each of the springs (10) has a corresponding first The magnets (5) of the two seats (4) that are fitted on the magnetic pole (3a) and the wavy length portions (16) of the protrusions (13, 14) are adjacent to each other. 4. The electric machine rotor according to claim 1, wherein the electric machine rotor acts on the electric machine.   The protrusions (13, 14) extend parallel to the main axis (R) and are aligned according to a cylindrical surface having an axis coinciding with the main axis (R). The rotor for electric machines according to claim 4. 6. The electric machine according to claim 1, wherein each of the first magnetic poles (3 a) has means (11) for engaging the spring (10). Rotor. The means (11) for engaging the spring (10) is in the form of a groove (11) on the surface (6) of the first magnetic pole (3a), and the protrusions (13, 14) are wherein is inserted into the groove (11), and said corrugated length portion (16) is characterized in that it has a convex portion facing the adjacent the seat (4) according to claim 4 or The rotor for an electric machine according to 5 .   The groove (11) extends parallel to the main axis (R) and is located on a cylindrical surface having an axis that coincides with the main axis (R). The rotor for electric machines described in 1. The magnet (5) is in the form of a parallelepiped and has a pair of parallel surfaces (8, 9) facing the corresponding parallel surfaces (6, 7) of the associated seat (4). a, and the spring (10), the surface (9) of the magnet relative to the plane of the corresponding second pole (3b) (7) defining said seat (4) (5) The rotor for an electric machine according to any one of claims 1 to 8, wherein the rotor is configured to be pressed. The rotor for an electric machine according to any one of claims 1 to 9, wherein the spring (10) comprises a plurality of springs (10) made of a ferromagnetic material. The rotor for an electric machine according to any one of claims 1 to 10, wherein the spring (10) comprises a plurality of springs (10) made of a metal strip. The rotor for an electric machine according to any one of claims 1 to 11, wherein the spring (10) comprises a plurality of springs (10) made of spring wires. Disposing the spring across each of the first magnetic poles (3a);
Placing each magnet (5) on said seat (4);
13. A method for assembling a rotor for an electric machine according to any one of the preceding claims, comprising inserting the magnet (5) into the seat (4).   14. Method according to claim 13, characterized in that the inserting step occurs simultaneously for all the magnets (5). Using a hole (21) to relatively fix the first magnetic pole (3a) and the second magnetic pole (3b) , and the inserting step includes one magnet (5 15. The method according to claim 13 or 14, wherein:

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